Piezoelectric harvest ice maker

ABSTRACT

An apparatus includes a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice. The mold body has a plurality of natural frequencies of vibration. Also included is an ice discharge mechanism configured to cause the ice to be removed from the at least one cavity. Also included is a vibration source mounted to the mold body at a location which is located near a region of high deflection at one of the first five natural frequency of vibration of the mold body; the location is also not a node at that natural frequency of vibration of the mold body. A refrigerator using the apparatus, a method of using the apparatus, and a method of designing the apparatus are also disclosed.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to refrigeration, and more particularly to icemakers and the like.

It is now common practice in the art of refrigerators to provide an automatic icemaker. The icemaker is often disposed in the freezer compartment and ice is often dispensed through an opening in the access door of the freezer compartment. In this arrangement, ice is formed by freezing water with cold air in the freezer compartment.

BRIEF DESCRIPTION OF THE INVENTION

As described herein, the exemplary embodiments of the present invention overcome one or more disadvantages known in the art.

One aspect of the present invention relates to an apparatus comprising a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice; and an ice discharge mechanism configured to cause the ice to be removed from the at least one cavity. The mold body has a plurality of natural frequencies of vibration. Also included is a vibration source mounted to the mold body at a location which is located near a region of high deflection at one of the first five natural frequencies of vibration of the mold body, which location is not a node at that particular one of the first five natural frequencies of vibration of the mold body.

Another aspect relates to a refrigerator comprising a body defining at least one cooled compartment; a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice, the mold body being in thermal communication with the at least one cooled compartment; and an ice discharge mechanism, mounted to the body of the refrigerator, which is configured to cause the ice to be removed from the at least one cavity. The mold body has a plurality of natural frequencies of vibration. Also included is a vibration source mounted to the mold body at a location which is located near a region of high deflection at one of the first five natural frequencies of vibration of the mold body, which location is not a node at that particular one of the first five natural frequencies of vibration of the mold body.

Still another aspect relates to an apparatus comprising a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice; and an ice discharge mechanism configured to cause the ice to be removed from the at least one cavity. Also included are a piezoelectric transducer mounted to the mold body and a controller configured to cause the ice discharge mechanism to cause the ice to be removed from the at least one cavity and to cause the piezoelectric transducer to vibrate the mold body.

Yet another aspect relates to a method comprising the steps of filling at least one cavity of a mold body with water to be frozen into ice; allowing the water to freeze into ice; and activating an ice discharge mechanism configured to cause the ice to be removed from the at least one cavity. The mold body has a plurality of natural frequencies of vibration. An additional step includes vibrating the mold body by applying a vibration source at a location which is located on the mold body near a region of high deflection at one of the first five natural frequencies of vibration of the mold body, the location not being a node that particular one of the first five natural frequencies of vibration of the mold body, the vibration source vibrating near that particular one of the first five natural frequencies of vibration of the mold body. The vibration is carried out to assist in the removal of the ice from the at least one cavity.

A further aspect relates to a method comprising the steps of carrying out at least one of modal analysis and prototype testing to determine at least one mode shape and at least one corresponding natural frequency of vibration of an ice mold body having at least one cavity for receiving water to be frozen into ice; specifying the at least one corresponding natural frequency as a target operating frequency for a vibration source; and specifying a location of the vibration source on the mold body near a region of high deflection at the at least one corresponding natural frequency of the mold body, the location not being a node at the natural frequency of vibration of the mold body, the location being determined from the at least one of modal analysis and prototype testing.

These and other aspects and advantages of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Moreover, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a left side cross-sectional view of a freezer compartment of a side-by-side refrigerator, according to an aspect of the invention;

FIG. 2 is a front view of the freezer compartment of FIG. 1, with the freezer compartment door open;

FIG. 3 is a right side cross-sectional view of the freezer compartment of FIG. 1;

FIG. 4 is a perspective view of the interior of the freezer compartment door with an icemaker in accordance with an aspect of the invention;

FIG. 5 is a close-up view of the upper portion of the door of FIG. 4;

FIG. 6 is a perspective view of the icemaker;

FIG. 7 is a side elevation of the icemaker in a fill and freeze mode;

FIG. 8 is a side elevation of the icemaker in a dispense mode;

FIGS. 9-12 show a cantilevered beam and exemplary mode shapes for vertical flexure of such beam;

FIG. 13 shows details of an exemplary piezoelectric transducer;

FIG. 14 is a top view of an exemplary rake-type icemaker; and

FIG. 15 is a view along line XV-XV in FIG. 14.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION

Reference should initially be had to FIGS. 1-3. In one or more embodiments, an icemaker is provided with a piezoelectric transducer or the like. Further details are provided below.

FIGS. 1-3 illustrate the freezer compartment 108 of a “side-by-side” refrigerator. The refrigerator is cooled by a conventional vapor-compression mechanical refrigeration cycle (although embodiments could also be used with other types of refrigerators, such as those cooled using thermoelectric cooling). The present invention is therefore not intended to be limited to any particular type or configuration of a refrigerator. In a well-known manner, the conventional vapor-compression mechanical refrigeration cycle includes condenser 102 for rejecting heat to ambient and evaporator 103 for absorbing heat from freezer compartment 108 to cool same. Air can pass over evaporator 103 in a conventional fashion. The compressor and expansion valve are omitted but are well known to the skilled artisan.

The freezer compartment 108 and a fresh food compartment (not shown but also well known to the skilled artisan) are arranged in a side-by-side configuration where the freezer compartment 108 is disposed next to the fresh food compartment. The door closing the freezer compartment is omitted in FIGS. 1-3, but can be hinged and sealed to the body in a conventional fashion.

The fresh food compartment and the freezer compartment 108 are, in a well-known manner, contained within a main body including an outer case, which can be formed by folding a sheet of a suitable material, such as pre-painted steel, into a generally inverted U-shape to form a top and two sidewalls of the outer case. The outer case also has a bottom which connects the two sidewalk to each other at the bottom edges thereof, and a back. A mullion or divider connects the top and bottom to each other and separates the fresh food compartment from the freezer compartment 108. As is known in the art, a thermally insulating liner is affixed to the outer case.

Suitable racks or shelves 109 are provided within freezer compartment 108 to hold frozen foods or the like. In a preferred approach, an icemaker with a piezoelectric transducer is located in the freezer compartment door, as seen in FIGS. 4 and 5 and discussed below. In some alternatives, a dedicated region 134 is optionally provided for the icemaker within freezer compartment 108 or even within the fresh food compartment or the door of the fresh food compartment; in the latter case, auxiliary cooling via ducted air, a separate evaporator, or the like can be provided in order to freeze the ice.

Thus, reference should now be had to FIGS. 4 and 5 depicting door 110 of freezer compartment 108. An icemaker with a piezoelectric transducer, to be discussed further below, is located in an upper region of door 110 above a hopper 112 to receive ice discharged therefrom. A suitable fill cup (not shown) can be provided in a well-known manner to supply water to the icemaker. The icemaker includes an ice mold body 104 pivoting about an axle 198, and a mounting bracket 196, as well as other components best seen in other figures and discussed further below.

FIG. 6 shows the icemaker in greater detail. Mold body 104 includes a plurality of mold cavities 160 for receiving water to be frozen into ice. Mold body rotates about axle 198 under the action of motor 146 coupled to mold body 104 through gearing arrangement 148.

As best seen in FIG. 7, in a first position, mold body 104 is upright with cavities 160 having their openings on the top and disposed to receive water to be frozen into ice. At least one piezoelectric transducer 114 is located on ice mold body 104. Transducer 114 can optionally be actuated by controller 197 when water in cavities 160 is freezing, so as to reduce the number of air bubbles frozen therein, producing clearer ice cubes. As seen in the detail in FIG. 13, transducer 114 includes a piezoelectric element 116 with backing material 118, secured to ice mold body 104 via wear plate 120. Leads 122 provide power upon actuation by controller 197 (power may come, for example, directly from controller 197 or from a separate power supply upon actuation by controller 197).

As best seen in FIG. 8, in a second position, mold body 104 is inverted with cavities 160 having their openings on the bottom and disposed to discharge ice (e.g., by gravity into hopper 112). Piezoelectric transducer 114 may be actuated by controller 197 when it is desired to discharge the ice, to help overcome any static friction or adhesion between the ice and the mold body 104. This actuation of the transducer 114 can preferably be done just before it is desired to discharge the ice, in some cases, while mold body is still upright as in FIG. 7, or while the mold body is rotating between the two positions, or after the mold body is in the discharge position of FIG. 8, or in any combination of conditions just described.

Water in mold body 104 must be chilled below the freezing point of water at ambient pressure; for example, by being located in freezer compartment 108 or a suitably cold auxiliary compartment 134 as described above. Ice in hopper 112 may be in or accessible from the door 110 of the freezer compartment 108 in a well known manner.

Note that instead of a side-by-side configuration, the freezer compartment 108 and the fresh food compartment could be arranged in a configuration where the freezer compartment 108 is disposed beneath the fresh food compartment or on top of same.

Controller 197 activates motor 146 just long enough to move the assembly back and forth between the fill and dispense modes. Controller 197 also turns transducer 114 on and off at appropriate times.

It will thus be appreciated, with reference again to FIGS. 1-3, that ice making assemblies in accordance with one or more embodiments of the invention can be positioned in a variety of locations, which may be similar to the positions of ice making assemblies on current refrigerators. These include, for example, the top corner of the freezer compartment, within the fresh food or freezer compartment doors, and so on. The footprint of ice making assemblies in accordance with one or more embodiments of the invention can, in at least some instances, be similar to those of current ice makers.

Many alternative forms of ice mold bodies are possible, forming, for example, cubes or other conventional or novel ice shapes.

It will thus be appreciated that in one or more embodiments, an icemaker has a piezoelectric transducer 114 which causes vibration (and deformation) of mold body 104, to cause ice cubes to fall out of mold body 104; i.e., mold body 104 itself distorts under the action of transducer 114, rather than merely acting as a rigid body vibrating on its mountings. In a preferred but non-limiting approach, the frequency of the input signal to transducer 114 is deliberately selected to match (i.e., be at or close to) one of the natural frequencies of vibration of mold body 104, as will be discussed further below. This results in a relatively large displacement for a small power input to the transducer. In other instances, the frequency might be other than a natural frequency.

In a preferred but non-limiting approach, mold body 104 is coated with nano-ceramic coating or material exhibiting hydrophobicity and/or has a low friction surface to minimize bonding and/or friction between ice and mold body 104, thereby aiding in harvesting of the ice.

As alluded to above, it is desired to maximize the response of ice mold body 104 to the input from the piezoelectric transducer. Accordingly, in one or more embodiments, a modal analysis is performed on the ice mold to find where nodal points are located for given modes of vibration, to maximize response, the transducer should be located near points of maximum deflection and not near node points (such points of maximum deflection are also known as anti-nodal points).

For illustrative purposes, FIGS. 10-12 show exemplary mode shapes for vertical flexure of a cantilevered beam shown in FIG. 9. The beam is shown in FIG. 9. The first three mode shapes are shown in FIGS. 10-12, corresponding to the first three natural frequencies ω₁, ω₂, and ω₃. Treating the ice mold 104 as a cantilevered beam for simplicity it can be seen in FIG. 10 that if it was desired to excite the mold body at the first natural frequency, then the transducer 114 should be located at or near the free end 251 and not near the built-in end 252. If it was desired to excite the mold body at the second natural frequency, then, as in FIG. 11, the transducer 114 should be located at or near the free end 251 or point of high deflection 253, and not near the built-in end 252 or node 254. If it was desired to excite the mold body at the third natural frequency, then, as in FIG. 12, the transducer 114 should be located at or near the free end 251 or points of high deflection 255, 256, and not near the built-in end 252 or nodes 257, 258.

Note that FIGS. 9-12 are illustrative; in some instances, the tray may be constrained differently. Regardless of constraints, the tray will vibrate. The frequency will change depending on boundary conditions. In determining anti-nodal points, the system level boundary conditions should be considered. Modal analysis is preferably performed with actual boundary conditions (as installed).

In one or more embodiments, by locating the transducer 114 as described (away from nodes and at or near points of high deflection for a given natural frequency), and/or by exciting the transducer at or near such natural, only a relatively small piezoelectric input is needed to cause a significant vibrational response of mold 104, sufficient to loosen the ice for harvest (such that the ice falls out by gravity). This effect also advantageously can result in energy and/or cost savings as compared to arrangements employing harvest heaters, depending on transducer cost and power consumption.

In one or more embodiments, to locate one or more transducers 114 on ice mold body 104, first carry out a modal analysis using a finite element program such as the well-known ANSYS® software (registered mark) available from Ansys, Inc. Canonsburg, Pa., USA, to find natural frequencies and modes (or employ an analytical solution, if available for the shape of the ice mold in question). Then, on a prototype, carry out physical tests to verify the predicted natural frequencies and mode shapes, using, for example, solutions such as those available from LMS International N.V. of Leuven, Belgium. Locate one or more transducers away from nodal points at the natural frequency of interest and at anti-nodal points (points of maximum deflection). In one or more embodiments, it may be desirable to operate at the first natural frequency, or at least one of the lower natural frequencies, to minimize the number of nodal points and increase the vibrational response to the input from the transducer.

The ability to achieve sufficient vibrational response to help form clear ice and/or to assist in harvest, while using only a relatively small transducer or transducers, due to appropriate placement thereof and selection of appropriate drive frequencies therefor, is a significant aspect of one or more embodiments of the invention. Given the teachings herein, the skilled artisan can specify requirements for a piezoelectric transducer or other vibration source to a manufacturer of same and obtain an appropriate unit.

Again, for the avoidance of doubt, in one or more embodiments, the mold body 104 itself undergoes vibration in one or more of torsional, vertical flexure, and horizontal flexure modes and does not merely vibrate as a rigid mass on an elastic mount.

One or more embodiments thus provide an ice maker with a coupled source of vibration that allows the release of ice via the vibration produced by a piezoelectric transducer or similar vibration source device. The vibrations can also be used during the ice making process to stimulate the removal of air from the water and in this way produce clear ice. The vibration source is preferably coupled to an area of the mold and preferably, while the water freezes the transducer is energized to allow air to leave the water and produce clear ice. For harvesting, the mold preferably turns and the piezoelectric transducer is preferably energized. The vibration breaks the static friction between the mold and the ice and releases the cubes. One or more embodiments enable release of complex shapes without mechanical action on the mold and/or the ability to harvest ice that is not clouded or white in color due to trapped air and minerals. One or more embodiments provide an approach to ice making for unconventional shapes that can also be applied to the common crescent ice shape or other shapes.

One or more embodiments can be used with different kinds of icemakers; for example, so-called rake icemakers. The rake icemaker is known, for example, from US Patent Publication 2010/0154458, the complete disclosure of which is expressly incorporated herein by reference in its entirety for all purposes. FIGS. 14 and 15 show an example of such an arrangement. The icemaker 202 includes a motor 210 and an ice mold body 211. The ice mold body 211 has a front side 2111, a back side 2111, and two end sides 2113. One of the end sides 2113 is attached to the motor 210, and the other is disposed remote from the motor 210.

The ice mold body 211 also has a bottom wall 212 with its curved inner surface 213 extending generally longitudinally along the length of the ice mold body 211, and a plurality of partial partition walls 214 extending transversely across the ice mold body 211 to define a plurality of ice chambers 215. As is known in the art, ice cubes can be formed in these ice chambers 215. Each partial partition wall 214 preferably has a recessed upper edge portion (not shown) through which water flows successively from one ice chamber to the next to fill all of the ice chambers 215. The icemaker 202 can have a water inlet element 216 supported by the ice mold body 211 for directing water from the water supply conduit into the ice chambers 215 as is known in the art.

As clearly shown in FIG. 14, each ice chamber 215 preferably has a generally race-track shaped top opening 220 terminating at the top surface 2114 of the ice mold body 211. In this embodiment, each top opening 220 has a substantially semi-circular frontal portion 2201 adjacent the front side 2111, and a substantially semi-circular back portion 2202 adjacent the back side 2112.

The icemaker 202 also has an ice stripper 221, which is disposed along the front side 2111 of the ice mold body 211 and partially covers the top openings 220. As clearly shown in FIG. 15, the ice stripper 221 preferably extends upward and inward from the front side 2111 as is known in the art. As illustrated in FIG. 14, in this embodiment, the ice stripper 221 has a plurality of stripper fingers 2211 preferably disposed over and aligned with the respective partial partition walls 214, and a plurality of covers 2212. Each cover 2212 is disposed between two adjacent stripper fingers 2211 for substantially completely covering the respective frontal portion 2201. The stripper fingers 2211 are longer than the covers 2212. The covers 2212 are used to prevent or substantially reduce water spillage (i.e., unfrozen water flowing out of the icemaker 202) when the door is opened or closed.

The icemaker 202 also has an ice rake or ejector 222 including a rotatable shaft 2221 disposed preferably slightly above the ice chambers 215 and at approximately midway between the frontal portions 2201 and the back portions 2202, and a plurality of rake fingers 2222 extending radially outwardly from the shaft 2221 and over the respective ice chambers 215. In this embodiment, each rake finger 2222 has a length so that it extends into the gap formed between the two respective adjacent stripper fingers 2211, but it does not touch the respective cover 2212 when the shaft 2221 rotates 360 degrees. One end of the shaft 2221 is connected to the axle 2101 of the motor 210. As is known in the art, when the motor 210 is activated, it rotates the shaft 2221, and the rake fingers 2222 move ice cubes from the respective ice chambers 215 to the ice stripper 221 during ice harvesting. In this embodiment, the motor 210 is an AC motor, and the shaft 2221 rotates approximately 360 degrees in a harvesting cycle. The icemaker 202 preferably has a heating element (not shown) which is used to heat ice mold body 211 when a harvest cycle begins in order to slightly melt ice cubes to allow the ice cubes to be more easily released from the ice chambers 215. In addition to or in lieu of the heating element, one or more piezoelectric transducers 114 can be provided in a suitable location, such as on mold body 211. The transducer(s) and motor 210 can be controlled, for example, by a controller such as 197 as described above.

One advantage that may be realized in the practice of some embodiments of the described systems and techniques is reduced energy use since only small piezoelectric input is needed to loosen ice for harvest. Another advantage that may be realized in the practice of some embodiments of the described systems and techniques is cost savings, again since only small piezoelectric input is needed to loosen ice for harvest. Still another advantage that may be realized in the practice of some embodiments of the described systems and techniques is increased ice clarity by avoiding trapped air and minerals. Yet another advantage that may be realized in the practice of some embodiments of the described systems and techniques is release of complex shapes without conventional mechanical action on the mold.

Given the discussion thus far, it will be appreciated that, in general terms, an exemplary apparatus, according to one aspect of the invention, includes a mold body 104 with at least one cavity 160 configured and dimensioned to receive water to be frozen into ice. The mold body has a plurality of natural frequencies of vibration (inherently, under whatever boundary (mounting) conditions it is subject to). Also included is an ice discharge mechanism configured to cause the ice to be removed from the at least one cavity. A non-limiting example is an actuation arrangement (e.g., motor 146 with gearing arrangement 148) which causes the mold body to transition between first and second positions, as shown in FIGS. 7 and 8 respectively. In the first position, water can be introduced into the at least one cavity. In the second position, ice can be discharged from the at least one cavity. Other types of ice discharge mechanism are possible, such as, for example, a rake arrangement configured to rake the ice out of the at least one cavity, described elsewhere herein in connection with FIGS. 14 and 15.

Also included in the apparatus is a vibration source (piezoelectric transducer 114 is a non-limiting example) mounted to the mold body at a location which is located near a region of high deflection at one of the first five natural frequencies of vibration of the mold body; the location is also not a node at that particular one of the first five natural frequencies of vibration of the mold body. FIGS. 9-12 and accompanying text provide further exemplary details in this regard.

In a preferred approach, a controller 197 is configured to cause the ice discharge mechanism to cause the ice to be removed from the at least one cavity and to cause the vibration source to vibrate near the particular one of the first five natural frequencies of vibration.

The mold body can have a variety of configurations; in one or more embodiments, a plurality of cavities 160 are configured and dimensioned to receive water to be frozen into ice.

As noted, in some instances, the ice discharge mechanism is an actuation arrangement which causes the mold body to transition between first and second positions; the controller is preferably configured to cause the actuation arrangement to transition the mold body between the first and second positions.

In one or more instances, controller 197 is further configured to cause the vibration source to vibrate near the particular one of the first five natural frequencies of vibration at a time when the mold body is in the second position and/or at a time just prior to when the mold body is in the second position.

Furthermore, in at least some cases, the controller is further configured to cause the vibration source to vibrate near the particular one of the first five natural frequencies of vibration while the water is freezing into the ice.

It is preferred that a release coating be provided on the at least one cavity. A number of non-limiting examples have been discussed elsewhere; e.g., a nano-ceramic coating. Another non-limiting example is Thermolon® non-stick coating (registered mark of Thermolon Ltd., Kowloon, Hong Kong). Polytetrafluoroethylene (PTFE) or any other suitable non-stick coating could also be employed.

Furthermore, given the discussion thus far, it will be appreciated that, in general terms, an exemplary refrigerator according to still another aspect of the invention, includes a body defining at least one cooled compartment (e.g., 108, 134); and a mold body 104 with at least one cavity 160 configured and dimensioned to receive water to be frozen into ice. The mold body is in thermal communication with the at least one cooled compartment and has a plurality of natural frequencies of vibration. Also included is an ice discharge mechanism, such as that described above, mounted to the body of the refrigerator (for example, via bracket 196). As used herein, including the claims, mounting to the body includes direct attachment to the body or indirect attachment to the body, such as to a door hinged to the body or the like. As described above, in some instances, the actuation arrangement causes the mold body to transition between first and second positions (or causes the rake to rake the ice out of the mold, or the like). Also included is a vibration source, as described above (element 114 is a non-limiting example), mounted to the mold body at a location which is located near a region of high deflection at one of the first five natural frequencies of vibration of the mold body, the location not being a node at the particular one of the first five natural frequencies of vibration of the mold body.

The refrigerator can be provided with any of the additional components and/or features as described above with respect to the apparatus.

Still further, given the discussion thus far, it will be appreciated that, in general terms, another exemplary apparatus includes a mold body as described above, an ice discharge mechanism as described above, a piezoelectric transducer mounted to the mold body; and a controller configured to cause the ice discharge mechanism to cause the ice to be removed from the at least one cavity and to cause the piezoelectric transducer to vibrate the mold body. In this aspect, the piezoelectric transducer may be provided in a variety of locations which may or may not conform to the general philosophy of locating near a region of high deflection at a natural frequency of vibration of the mold body which is also not a node at the natural frequency of vibration of the mold body.

Yet further, given the discussion thus far, it will be appreciated that, in general terms, a exemplary method includes the steps of filling at least one cavity of a mold body with water to be frozen into ice (in at least some instances, while the mold body is in an upright position, as in FIG. 7); allowing the water to freeze into ice; and activating an ice discharge mechanism configured to cause the ice to be removed from the at least one cavity. The mold body has a plurality of natural frequencies of vibration. An additional step includes vibrating the mold body by applying a vibration source (piezoelectric transducer 114 is a non-limiting example) at a location which is located on the mold body near a region of high deflection at one of the first five natural frequencies of vibration of the mold body, the location not being a node at the particular one of the first five natural frequencies of vibration of the mold body, the vibration source vibrating near the particular one of the first five natural frequencies of vibration of the mold body. The vibration is carried out to assist in the removal of the ice form the at least one cavity. The vibration source location or locations can be determined, for example, as described with respect to FIGS. 9-12. As used herein, including the claims, the vibration source matching, being close to, or vibrating “near” the natural frequency of vibration of the mold body includes vibrating at the natural frequency or sufficiently close thereto to produce an adequate vibrational response in the mold body 104 so as to aid ice release and/or reduce clouding. Similar comments apply to the location of the transducer or other vibration source. In some instances, the vibration source vibrates at a frequency that is within +/−2% of the corresponding natural frequency of the mold body. Furthermore, in some instances, the geometric center of the transducer or other vibration source is within plus or minus 5 mm of the anti-nodal location.

In at least some instances, the ice discharge mechanism is an actuation arrangement as described above and the vibrating step is carried out at a time when the mold body is in the second position and/or a time just prior to when the mold body is in the second position.

In at least some embodiments, the vibrating step is further carried out while the water is freezing into the ice.

Even further, given the discussion thus far, it will be appreciated that, in general terms, another exemplary method includes the steps of carrying out at least one of modal analysis and prototype testing to determine at least one mode shape and at least one corresponding natural frequency of vibration of an ice mold body 104 having at least one cavity 106 for receiving water to be frozen into ice; specifying the at least one corresponding natural frequency as a target operating frequency for a vibration source (transducer 114 is a non-limiting example); and specifying a location of the vibration source on the mold body near a region of high deflection at the at least one corresponding natural frequency of the mold body (the location is not a node at the natural frequency of vibration of the mold body). The location is determined from the aforementioned modal analysis and/or prototype testing, for example, as described with respect to FIGS. 9-12.

Software includes but is not limited to firmware, resident software, microcode, etc. As is known in the art, part or all of one or more aspects of the methods and apparatus discussed herein may be distributed as an article of manufacture that itself comprises a tangible computer readable recordable storage medium having computer readable code means embodied thereon. The computer readable program code means is operable, in conjunction with a computer system or microprocessor, to carry out all or some of the steps to perform the methods or create the apparatuses discussed herein. A computer-usable medium may, in general, be a recordable medium (e.g., floppy disks, hard drives, compact disks, EEPROMs, or memory cards) or may be a transmission medium (e.g., a network comprising fiber-optics, the world-wide web, cables, or a wireless channel using time-division multiple access, code-division multiple access, or other radio-frequency channel). Any medium known or developed that can store information suitable for use with a computer system may be used. The computer-readable code means is any mechanism for allowing a computer or processor to read instructions and data, such as magnetic variations on a magnetic medium or height variations on the surface of a compact disk. The medium can be distributed on multiple physical devices (or over multiple networks). As used herein, a tangible computer-readable recordable storage medium is intended to encompass a recordable medium, examples of which are set forth above, but is not intended to encompass a transmission medium or disembodied signal. A processor may include and/or be coupled to a suitable memory. A processor with suitable software and/or firmware instructions may be used to implement controller 197. Other types of controls, such as electromechanical controls, could also be used.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to exemplary embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. Moreover, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Furthermore, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto. 

What is claimed is:
 1. An apparatus comprising: a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice, said mold body having a plurality of natural frequencies of vibration; an ice discharge mechanism configured to cause said ice to be removed from said at least one cavity; and a vibration source mounted to said mold body at a location which is located near a region of high deflection at one of the first five natural frequencies of vibration of said mold body, said location not being a node at said one of the first five natural frequencies of vibration of said mold body.
 2. The apparatus of claim 1, further comprising a controller configured to cause said ice discharge mechanism to cause said ice to be removed from said at least one cavity and to cause said vibration source to vibrate near said one of said first five natural frequencies of vibration of said mold body.
 3. The apparatus of claim 2, wherein said mold body has a plurality of cavities configured and dimensioned to receive said water to be frozen into said ice.
 4. The apparatus of claim 2, wherein: said ice discharge mechanism comprises an actuation arrangement, mounted to said body of said refrigerator, which causes said mold body to transition between: a first position wherein said water can be introduced into said at least one cavity; and a second position wherein said ice can be discharged from said at least one cavity; and said controller is configured to cause said actuation arrangement to transition said mold body between said first and second positions.
 5. The apparatus of claim 4, wherein said controller is further configured to cause said vibration source to vibrate near said one of the first five natural frequencies of vibration at least one of: a time when said mold body is in said second position; and a time just prior to when said mold body is in said second position.
 6. The apparatus of claim 2, wherein said controller is further configured to cause said vibration source to vibrate near said one of the first five natural frequencies of vibration while said water is freezing into said ice.
 7. The apparatus of claim 2, wherein said vibration source comprises a piezoelectric transducer.
 8. The apparatus of claim 2, further comprising a release coating on said at least one cavity.
 9. The apparatus of claim 2, wherein: said ice discharge mechanism comprises a rake arrangement configured to rake said ice out of said at least one cavity.
 10. A refrigerator comprising: a body defining at least one cooled compartment; a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice, said mold body having a plurality of natural frequencies of vibration, said mold body being in thermal communication with said at least one cooled compartment; an ice discharge mechanism, mounted to said body of said refrigerator, and configured to cause said ice to be removed from said at least one cavity; a vibration source mounted to said mold body at a location which is located near a region of high deflection at one of the first five natural frequencies of vibration of said mold body, said location not being a node at said one of the first five natural frequencies of said mold body.
 11. The refrigerator of claim 10, further comprising a controller configured to cause said ice discharge mechanism to cause said ice to be removed from said at least one cavity and to cause said vibration source to vibrate near said one of said first five natural frequencies of vibration of said mold body.
 12. The refrigerator of claim 11, wherein said mold body has a plurality of cavities configured and dimensioned to receive said water to be frozen into said ice.
 13. The refrigerator of claim 11, wherein: said ice discharge mechanism comprises an actuation arrangement, mounted to said body of said refrigerator, which causes said mold body to transition between: a first position wherein said water can be introduced into said at least one cavity; and a second position wherein said ice can be discharged from said at least one cavity; and said controller is configured to cause said actuation arrangement to transition said mold body between said first and second positions.
 14. The refrigerator of claim 13, wherein said controller is further configured to cause said vibration source to vibrate near said one of the first five natural frequencies at least one of: a time when said mold body is in said second position; and a time just prior to when said mold body is in said second position.
 15. The refrigerator of claim 11, wherein said controller is further configured to cause said vibration source to vibrate near said one of the first five natural frequencies while said water is freezing into said ice.
 16. The refrigerator of claim 11, wherein said vibration source comprises a piezoelectric transducer.
 17. The refrigerator of claim 11, further comprising a release coating on said at least one cavity.
 18. The refrigerator of claim 11, wherein: said ice discharge mechanism comprises a rake arrangement configured to rake said ice out of said at least one cavity.
 19. An apparatus comprising: a mold body with at least one cavity configured and dimensioned to receive water to be frozen into ice; an ice discharge mechanism configured to cause said ice to be removed from said at least one cavity; a piezoelectric transducer mounted to said mold body; and a controller configured to cause said ice discharge mechanism to cause said ice to be removed from said at least one cavity and to cause said piezoelectric transducer to vibrate said mold body.
 20. The apparatus of claim 19, further comprising a release coating on said at least one cavity.
 21. A method comprising the steps of: filling at least one cavity of a mold body with water to be frozen into ice, said mold body having a plurality of natural frequencies of vibration; allowing said water to freeze into said ice; activating an ice discharge mechanism configured to cause said ice to be removed from said at least one cavity; and vibrating said mold body by applying a vibration source at a location which is located on said mold body near a region of high deflection at one of the first five natural frequencies of vibration of said mold body, said location not being a node at said one of the first five natural frequencies of vibration of said mold body, said vibration source vibrating near said one of the first five natural frequencies of vibration of said mold body, said vibration being carried out to assist in said removal of said ice from said at least one cavity.
 22. The method of claim 21, wherein: in said activating step, said ice discharge mechanism comprises an actuation arrangement which causes said mold body to transition between: a first position wherein said water can be introduced into said at least one cavity; and a second position wherein said ice can be discharged from said at least one cavity; and said vibrating step is carried out at least one of: a time when said mold body is in said second position; and a time just prior to when said mold body is in said second position.
 23. The method of claim 22, wherein said vibrating step is further carried out while said water is freezing into said ice.
 24. The method of claim 21, wherein said vibration source in said vibrating step comprises a piezoelectric transducer.
 25. A method comprising the steps of: carrying out at least one of modal analysis and prototype testing to determine at least one mode shape and at least one corresponding natural frequency of vibration of an ice mold body having at least one cavity for receiving water to be frozen into ice; specifying said at least one corresponding natural frequency as a target operating frequency for a vibration source; and specifying a location of said vibration source on said mold body near a region of high deflection at said at least one corresponding natural frequency of said mold body, said location not being a node at said natural frequency of vibration of said mold body, said location being determined from said at least one of modal analysis and prototype testing. 